Layout jig for stair stringers



May 10, 1966 G. M. WATSON LAYOUT JIG FOR STAIR STRINGERS Filed March 5, 1964 FIG. 2

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INVENTOR GORDON M. WATSON MWM W ATTORNEY United States Patent 3,250,014 LAYOUT JIG FOR STAIR STRINGERS Gordon M. Watson, 7820 Harlan, St. Louis, Mo. Filed Mar. 5, 1964, Ser. No. 349,619 2 Claims. (Cl. 33-192) This invention relates to stringer construction. In building a stairway the usual practice is to employ two stringers, one at each side of the stairway. These stringers are cut out so as to provide supporting portions for the treads of the stairs, or steps, and the risers, the cuts being made at right angles to each other.

The building of stringers is not too diflicult if the case is one of even numbers. For example if there are to be ten stair treads in a height of five feet and a length of ten feet.

However it seldom works out in practice that even numbers are involved. More likely the-re will be seventeen stair treads in :a height of nine feet three and one-half inches and a length of fifteen feet eight and three-quarters inches; Such a problem requires the efforts of a skilled workman and also requires a considerable expenditure of time. Thus the making of the layout for a stair stringer 'becomes an expensive procedure.

One of the principal objects of this invention is to provide a layout jig or layout tool which may be automatically applied to layout stair stringers of any required dimensions.

Another object of my invention is to provide a layout jig which will automatically subdivide any given height into a given number of heights of stair risers with one setting of the layout jig.

Another object of my invention is to provide a layout jig which will automatically subdivide any given horizontal length of a stair stringer into a given number of lengths of stair treads with one setting of the layout jig.

A further object of my invention is to use a multiplicity 0f pivoted levers to form a set of linkages to simulate in exact size the distances required to layout the required stair stringers for any given combination of stair treads and stair risers.

A still vfurther further object of my invention is to provide a layout jig for stair stringers which will be adapted to work from the measurements of any two fixed sides of a triangle to provide the third side automatically. It will be recognized that commonly the length of a stair stringer is given in terms of the hypotenuse of the triangle which is formed by the vertical height of the stairway and the horizontal length of that stairway. With my invention it is only necessary to know the number of stairs, the length of the stringer, and the tread width to automatically dbtain the riser height.

Conversely, with my invention if the number of stairs is known and the length of the stringer isgiven, the

' knowledge of the riser height will enable the operator to automatically find the proper tread width required for a perfectly proportioned stairway.

An additional object of my invention is to provide a layout jig for stair stringers which will operate to proportion such stringers properly and independently of the material of the stringers, that is which will work satisfactorily with wood, metal, or concrete stair stringers.

The above, and other additional objects will be apparent to those skilled in the art of constructing stair FIGURE 2 is a side elevational view of the set screwhandle at the bottom of FIGURE 1;

FIGURE 3 is a side elevational view of the riser and tread adjustment mechanism of FIGURE 1; and

FIGURE 4 is a side eleva-t-ional view of a typical stair stringer.

Referring now to FIGURE 1, numeral 1 is given to the main bar. Main bar 1 carries a set of hinge pins 2, 3, 4, 5, and 6. The hinge pins 2, 3, 4, 5, and 6 are mounted respectively upon the spacer blocks 7, 8, 9, 10, and 11. These spacer blocks are slidable lengthwise upon the main bar 1.

Similarly I provide an outside bar 12, which carries a carries a set of binge pins 13, 14, 15, 16, and 17. The

outside bar pins are mounted respectively upon the outside spacer blocks 18, 19, 20, 21, and 22. The outside spacer blocks are slidable lengthwise upon the outside bar 12.

A number of expandable and contractable linkages are provided, which are suspended from the above described pins and spacer blocks. Each linkage consists solely of link members in combination. Each spacer block and its associated hinge pin is adapted to carry two link members although at each bar at one'end there will'be only one link member termination. The construction of the link members and the manner of their attachment to the hinge pins is best seen in FIGURE 2.

For the embodiment of my invention described I have shown main and outsidebars carrying each a set of five spacer blocks. Accordingly I provide a set of five L- shaped guide members, mounted upon the link members to be described and suspended therefor upon the hinge stringers. The invention consists in the novel features and t pins previously described. The L-shaped guide members are numbered 2 3, 24, 25, 2 6, and 27. A side view of guide member 25 is shown in FIGURE 3. There it will be seen that each guide member is provided-with a pair of hinge pms.

At the junction of its Lwshaped members, each guide member carries a hinge pin and center punch in combination. These hinge pins and combination center punches are numbered 28, 29, 30, 31, and 32 respectively. Each combination hinge pin and center punch ,of each L-shaped guide member is adapted to carry and ride upon two link members, which in turn are adapted to ride upon the main bar hinge pins described previously.

Therefore I provide a set of link members for the main bar spacer blocks and main bar hinge pins in the form of simple levers provided -with a hole at each end. The main bar link members are numbered 33, 34, 35, 36, 37, 38, 39, 40, and 41.

Link member 33 is mounted at one end on the hinge pin 2 and at the other on the hinge pin 28. Link member 34 is mounted at one end on the hinge pin 3 and at the other end on the hinge pin 28. Similarly link member 35 is mounted at one end on the hinge pin 3 and at the other end on the hinge pin and center punch 29. Link member 36 is mounted at one end on the hinge pin 4 and at the other end upon the hinge pin 29. Link member 37 is mounted at one end upon the hinge pin 4 and at the other end upon hinge pin and center punch 30. Link member 38 is mounted upon hinge pins 5 and 30. Link member 39 is mounted upon hinge pins 5 and 31. Link member 40 is mounted upon hinge pins 6 and 31. Link member 41 is mounted upon hinge pins 6 and 32.

To suspend the opposite ends of the L-shaped guide members, I provide a set of link members for the longer sides of the guide members, which connect or link to the spacer blocks on the outside bar 12. The outside bar link members are numbered 42, 43, 44, 45, 46, 47, 48, 49, 50, and 51.

I also provide aset of hinge pins on the longer sides of the L-shaped guide members. These hinge pins are numbered 52, 53, 54, 55, 56, and 57.

Link member 42 is mounted upon hinge pins 52 and 13. Link member 43 is mounted upon hinge pins 13 and 53. Link member 44 is mounted upon hinge pins 53 and 14. Link member 45 is mounted upon hinge pins 14 and 54. Link member 46 is mounted upon hinge pins 54 and 15. Link member 47 is mounted upon hinge pins 15 and 55. Link member 48 is mounted upon hinge pins 55 and 16. Link member 49 is mounted upon hinge pins 16 and 56. Link member 50 is mounted upon hinge pins 56 and 17. Link member 51 is included merely to show that the set may be extended indefinitely in the same sense as the previous members, where more guide members and longer main and outside bars are required.

On one of the outside bar spacer blocks 21, I provide a set screw with associated handle 72. The purpose of this set screw and handle is to be able to lock the block 21 in position with respect to the outside bar 12. It is obvious that this set screw and handle could be placed on any of the other spacer blocks to stabilize the positions of the expansible members.

On one of the L-shaped guide members I provide a calibrated scale, which is shown on the longer side of the L-shaped guide member 25 of FIGURE 1. Integrally mounted on opposite ends of the scale 58 are two bearing blocks 59 and 60. The bearing blocks 59 'and 60 carry the threaded rod 61, which is rotatable by means of the handle 62. A set screw 63 is provided upon the bearing block 59 which makes it possible to lock the threaded rod 61 and its handle 62 in any given position.

I provide a rider block 64 to ride upon the threaded rod 61. Integrally attached to the rider block 64 is the calibrated scale 65. The scale 65 is provided with a slot in which rides the hinge pin 29 of the L-shaped guide member 24. The hinge pin slot is numbered 66. There is a wing nut on hinge pin 29 and which I number 67. At the extremity of the centerline of the scale member 65 I imprint an arrow 68.

Now in operation, let us suppose that it is desired to solve the general problem of laying out a stair stringer as shown in FIGURE 4. The stringer is represented by numeral 69. This stringer is given the workline 70 which is the hypotenuse of a triangle. Along workline 70 there will be a given number of nosing points, which are the positions at which the risers and the treads meet. These nosing points correspond to the hinge points 28, 29, 30

and so forth of the FIGURE 1.

The workline is shown in FIGURE 1 to be represented by the distance between the hinge points 28 and 32. In

the example shown the jig is illustrated for five nosing points, thus there are five hinge pins 28, 29, 30, 31, 32, and these could be extended indefinitely.

To use the layout jig, one merely extends or compresses the jig until the proper number of nosing points fits exactly in the right distance, thus establishing the workline length. Thus if the workline length is to be six feet, the distance from pin 82 to pin 32 will be six feet. Thus the stringer will have a workline of six feet.

The tread width is set simply. This width is the length from the nosing point (or the combination hinge pin and center punch) to the riser line. This setting is accomplished by merely turning the handle 62 and thereby moving the arrow 68 on the calibrated scale 65 along the threaded rod 61 until the arrow points to the proper tread width measurement on the calibrated scale 58. Scale 58 is laid out to measure from the hinge pin and center punch 30 as zero.

Turning the handle 62 and rotating the threaded rod 61 has several effects. First it moves the scale 65 in a sense perpendicular to the threaded rod. Also it rotates this scale 65 about the hinge pin and center punch 29 on the workline, which means that it rotates it about the next nosing point. Since the distance from the arrow 68 to the nosing point represented by the pin 30 is fixed, that is the tread width is fixed, and since also the distance from the hinge pin 29 to the pin 30 was fixed by the original expansion or contraction of the jig, the turning of the handle has fixed the distance from the hinge pin 29 to the point on the scale 58 to which the arrow is pointing.

Conversely if the distance from the edge of the scale 58 to the center of the pin 29 is set, by the turning of the handle 62, this means that the riser height is set and the arrow 68 will point to the reading of the proper tread width on the scale 58. In the previous instance the tread width was established by turning the handle of the threaded rod and the riser height was found automatically (it being the distance from the nosing point 29 to the edge of the scale 58).

Once the proper dimensions have been established, it is only necessary to set the set screw handle 63, tighten the wingnuts 67 on the hinge pin 29 and 71 on the hinge pin 30, and the jig is ready to use. The layout tool or jig is placed on the work material and the center punches are struck making a record of the proper nosing distances and lines are drawn along the edges of the scales 58 and 65. The other centerpunches 28, 31, and 32 are also struck and the lines are drawn along the corresponding L-shaped guides 23, 24, 26, and 27, in the corresponding positions with respect to the scale members 58 and 65. It is not necessary tohave scales on each member as their proper lengths have been established by the turning of the handle 62.

There is really no need for both the scales 58 and 65. It is customary to merely specify the wordline length and the tread width. Thus two sides of the triangle composed of the riser height, tread width and distance between nosing points, are known. The third is worked out geometrically. If the two sides known are the distance between nosing points, and the riser height, the tread width will automatically be established by the device.

When not in use, the wing nuts and set screws are released and the device is collapsed for convenience.

It must be recognized that the above is a description of a geometric construction for solving the construction of a right triangle when two sides are known. The hypotenuse of the triangle is known because it is the workline divided by the number of nosing points minus one. This device automatically establishes the angles of the triangle also, but I do not provide a pair of protractor scales to measure the angles because it is not customary to read the angle measurements when constructing stairs.

The handiness of this machine is further aided by the fact that the range of measurements is generally between some well-established limits. For instance, it is never necessary to have risers of a height of three feet, nor treads of a width less than six or eight inches. Further the ranges are limited by the building codes.

I have illustrated but one embodiment of my machine. It was illustrated for a small number of nosing points, and it will be obvious to those skilled in the art of making stairway stringers that the machine can be extended indefinitely to provide a larger device for laying out stringers for stairways having dozens of stairs. Or conversely, the smaller layout jig can be used for a fraction of the stairway and the jig can simply be shifted by sliding the hinge pins and center punches along the workline to new positions.

Many variations and changes and modifications are possible in the invention and I do not intend that the invention be limited other than by the scope of the appended claims.

I claim:

1. In a layout jig for stairway stringers, a main bar and an outside bar, a set of main bar spacer blocks slidable on said main bar,

a set of hinge pins on said outside bar spacer blocks,

a set of L-shaped guide members. provided with a shorter arm and a longer arm,

a set of hinge pins and center punches on said guide members at the junction point of said shorter arm and said longer arm,

link members mounted at one end of the hinge pins in said main spacer blocks and-at the other end on the hinge pins at the junction point of said guide members,

a set of hinge pins on said guide members at the end of the longer arm thereof,

link members mounted at one end on the hinge pins in said outside spacer blocks and at the other end on the hinge pins on said guide members at the end of the longer arm thereof,

a pair of bearing blocks on the longer arm of one of said guide members,

a threaded rod mounted in and rotatable on said bearing blocks and a handle on said threaded rod,

a rider block on said threaded rod and movable longitudinally with respect to said threaded rod,

21 scale member integral with said rider block and disposed perpendicular to the longitudinal axis of said threaded rod, a slot in said scale member, the hinge pin and center punch of said next adjacent guide member disposed in and through said slot and both rotatable in and slidable in said slot in said scale member, and

a scale on said longer arm of said guide member carrying said threaded rod, along one'edge thereof.

2. The combination of claim 1 and further characterized by a scale on said scale member, measuring the distance between said center of said hinge pin in said slot and the edge of said longer arm of said next adjacent guide member carrying said first-mentioned scale.

References Cited by the Examiner UNITED STATES PATENTS ISAAC LISANN, Primary Examiner. 

1. IN A LAYOUT JIG FOR STAIRWAY STRINGERS, A MAIN BAR AND AN OUTSIDE BAR, SET OF MAIN BAR SPACER BLOCKS SLIDABLE ON SAID MAIN BAR, A SET OF HINGE PINS ON SAID MAIN BAR SPACER BLOCKS, A SET OF SPACER BLOCKS SLIDABLE ON SAID OUTSIDE BAR, A SET OF HINGE PINS ON SAID OUTSIDE BAR SPACER BLOCKS, A SET OF L-SHAPED GUIDE MEMBERS PROVIDED WITH A SHORTER ARM AND A LONGER ARM, A SET OF HINGE PINS AND CENTER PUNCHERS ON SAID GUIDE MEMBERS AT THE JUNCTION POINT OF SAID SHORTER ARM AND SAID LONGER ARM, LINK MEMBERS MOUNTED AT ONE END OF THE HINGE PINS IN SAID MAIN SPACER BLOCKS AND AT THE OTHER END ON THE HINGE PINS AT THE JUNCTION POINT OF SAID GUIDE MEMBERS, A SET OF HINGE PINS ON SAID GUIDE MEMBERS AT THE END OF THE LONGER ARM THEREOF, LINK MEMBERS MOUNTED AT ONE END OF THE HINGE PINS IN SAID OUTSIDE SPACER BLOCKS AND AT THE OTHER END ON THE HINGE PINS ON SAID GUIDE MEMBERS AT THE END OF THE LONGER ARM THEREOF, 